1. Field of the Invention
The present invention relates to a vehicle actuator holding structure for holding the piston rod of an actuator in a retracted condition, the actuator including a slave cylinder for use in operating a vehicle brake or clutch.
2. Description of the Related Art
Clutch master cylinders and slave cylinders are used in clutches as actuators in four-wheeled vehicles and when such a clutch is consigned to manufacturers, piping is employed beforehand for coupling the clutch master cylinder and the slave cylinder as a clutch piping system in such a condition that the clutch piping system has substantially been incorporated into a vehicle before being consigned to assembly manufacturers with the clutch piping system filled with working fluid.
The slave cylinder in the actuator is so constructed as to retract a piston rod through its housing by means of hydraulic fluid moving from the clutch master cylinder as a fluid-pressure generating source. In the pre-filled condition above, the piston rod is held in the retracted condition in the holding structure so that the piston rod is prevented from producing any backlash. Japanese Patent Laid-Open No. 2001-289206 discloses one of the examples as described above.
The holding structure has a first retainer attached to the housing of an actuator and a second retainer attached to a piston rod retractably contained in the housing. The first retainer includes a substantially annular assembly attached to a housing side opposite to the piston rod, a plurality of coupling leg pieces extending from the assembly toward the front end of the piston rod along the side of the housing, a first engaging portion formed at the front end of each coupling leg piece, and a lateral belt for coupling the plurality of coupling leg pieces by peripherally carrying the piston-rod side of the housing with its arm. A rupture portion is formed in the assembly and the lateral belt both and a second engaging portion is provided to the second retainer.
The retracted condition of the piston rod is held by joining the first engaging portion of the first retainer and the second engaging portion or the second retainer. When the first retainer is released from engaging with the second retainer by removing the first retainer from the housing, the piston rod is allowed to be extended and retracted.
However, as the first retainer used in the holding structure above is arranged such that the assembly is attached to the side of the housing opposite to the piston rod and that the lateral belt is attached to the piston rod side of the housing, the assembly and the lateral belt are coupled together by the use of the plurality of coupling leg pieces so as to form the external configuration of the housing accordingly. As a result, it is not feasible to appropriate the holding structure to any other housing different in configuration and a number of special parts are needed to be prepared for individual housings, which has resulted in lower productivity, safekeeping capacity and economic efficiency.
An object of the present invention is to provide an actuator holding structure for a vehicle, capable of being widely employed for many kinds of actuators different in configuration when the actuator for use in a vehicle brake or clutch is set in a pre-filled condition before the actuator is incorporated into the vehicle.
In order to accomplish the object above, there is provided An actuator holding structure for a vehicle, holding a piston rod retractably contained in a housing of an actuator in such a manner that the piston rod is held in the housing in a retracted condition and while the actuator is in operation, the retracted condition of the piston rod is released so that the piston rod is allowed to be extended and retracted, having: a first retainer attached to the housing; a second retainer attached to the piston rod; and, a plurality of protruded engaging portions formed on the outer peripheral surface of the housing, wherein the piston rod is held in the retracted condition while the first retainer and the second retainer are engaging together, and when the first retainer is released from engaging with the second retainer, and the piston rod is allowed to be extended and retracted, wherein the first retainer includes a first lateral belt for peripherally holding a part of the housing by engaging with the protruded engaging portions while the first retainer and the second retainer are engaging together, and a second lateral belt for peripherally holding the other part of the housing opposite to the first lateral belt so as to be latched and unlatched.
Further, the first retainer may be disposed in the vicinity of the retractable side of the piston rod of the housing, wherein a plurality of coupling leg pieces are projected from one of the first and second retainers, the coupling leg piece having a first engaging portion, whereas a second engaging portion for latching and unlatching the first engaging portion is provided to the other retainer. The first lateral belt may include a rupture portion for breaking apart the first retainer when the first retainer is removed. The first retainer may include a connection piece coupling both ends of the first lateral belt so as to keep the engaged condition of the second lateral belt when the first retainer is removed.